The present invention relates to a display unit which serves as an image display unit employed in a computer terminal or the like and has the function of communicating with computers such as a personal computer (hereinafter abbreviated as PC), a work station, etc.
As a conventional example of a display unit, which is related to communications with PC, may be mentioned an image display unit clearly shown in FIG. 7 in Japanese Patent Application Laid-Open No. Hei 5-232918. In this type of image display unit, a control signal based on interface specifications of a computer, which is outputted from a computer body, is inputted to a display control circuit of the image display unit. In such a case, the control signal inputted to the display control circuit is inputted based on the same interface specifications as those for an interface of the computer. Here, the interface specifications indicate specifications related to a command, data, etc. outputted from a communication apparatus, or specifications related to a command, data, etc. handleable by the communication apparatus.
Further, Japanese Patent Application Laid-Open No. Hei 7-302068 has clearly disclosed a display unit employed in a display system related to communications between each computer and the display unit. A non-volatile memory is installed in the display unit. Control codes related to height, width and brightness of an visual output at the display unit are stored in the non-volatile memory. Further, an identification code for allowing the computer to identify specifications for the display unit is also stored in the non-volatile memory. These information are read out as needed by the display system, and the computer recognizes the read information through the communications with the computer, thereby making it possible to control the display unit based on the information. The display unit aims to omit cumbersome image-quality adjustments such as horizontal and vertical display positions, display sizes, which are made by a user when the display unit is used, according to the above function.
However, the prior art had a restriction in that since a PC and a control circuit provided within the display unit directly communicated with each other, only specific serial interface specifications of the PC could handle or cope with them. Therefore, a problem arose in that in order to perform communications with a PC having other serial interface specifications, a control circuit compliant with new serial interface specifications needed to be re-developed as a control circuit having a display unit, and hence the period and cost required to develop it increased.
While video signals adapted to the present display unit or information about video signal timing have been stored in the non-volatile memory of the display unit shown as the conventional example, the use of the stored information alone would cause a problem of shortage in information such as the occurrence of trouble in the display unit in particular upon using the display unit.
Further, since there was no means for performing conversion between different interface specifications of commonly-used digital signal processing devices having communication functions under the present situation even as to communications based on the different serial interface specifications, the digital signal processing devices having the different interface specifications could not be connected.
On the other hand, Japanese Patent Application Laid-Open No. Hei 10-116139 has clearly disclosed a display unit having incorporated therein a Hub function of a USB (Universal Serial Bus) corresponding to a new interface of a PC, as another prior art. The Hub of the display unit comprises one UP port connected to an external computer, three Down ports to which peripheral apparatuses are connected, and a Hub control circuit. When the UP port of the Hub is connected to each external computer such as a PC or the like, the Hub gives identification information such as the maker""s name of the Hub, the product name thereof, its production number, the number of Down ports, etc. held in a Hub controller for performing the control of a Hub function within the Hub control circuit, to the external computer through the UP port as a reply to the external computer, whereby the external computer can recognize the Hub. In doing so, the external computer transfers an operation instruction to the Hub, so that the Down ports of the Hub can be used. When the peripheral apparatuses are connected to the Down ports of the Hub in this condition respectively, communications between the peripheral apparatuses and the external computer are allowed so that the peripheral apparatuses are activated.
However, the prior art has a problem in that since the Hub is recognized according to the maker name of the Hub, the product name thereof and its production number recorded in the Hub controller, general versatility is not obtained. When a display unit is shipped in the form of the brand name of another company, for example, it is necessary to rewrite the maker name or the like recorded in a Hub controller so as to coincide with that of the display unit for each shipment. Therefore, a problem arose in that a Hub having general versatility was not obtained and the manufacturing cost of the Hub would increase.
There is a possibility that since information about the specifications of the display unit should be originally held on the display unit side, the specifications information of the display unit, which has been held in the Hub, will differ from that of an actual display unit upon holding it on the Hub side, thus causing an inconsistency.
With the foregoing problems in view, an object of the present invention is to provide a display unit having high general versatility, which is adapted to interface specifications of communications with various computers.
Another object of the present invention is to provide a display unit excellent in maintenance, which is capable of obtaining various information inside the display unit.
A display unit according to the present invention for achieving the above objects is a display unit having a CPU and means for communicating with a computer, which comprises interface specifications converting means for performing mutual conversion between interface specifications about communications from the computer and interface specifications handleable by the CPU. Further, the interface specifications converting means can take such a structure as to be detachable from and attachable to the display unit. When the interface specifications of the computer are also changed to another upon replacement of the computer connected to the display unit with another, the interface specifications converting means can be replaced by another interface specifications converting means adapted to the interface specifications conversion.
Owing to such a structure, interface specifications of communications with various computers can be handled by the same display unit without the replacement and modification of the display unit. In terms of the function of performing the mutual conversion between the interface specifications of the computer and those of the display unit, the interface specifications converting means is not limited to the provision thereof within the display unit. The function of performing interface mutual conversion similar to the above is allowed to serve even by providing it on the computer side.
Thus, the display unit according to the present invention is capable of communicating with computers having interfaces with various specifications owing to the use of such interface specifications converting means. When viewed from the computer side, each computer is capable of communicating with display units having various interface specifications.
Described specifically, a serial interface adapter is provided in a display unit as interface specifications converting means. The serial interface adapter is capable of converting communication information about interface specifications from a computer to communication information about interface specifications suitable for a CPU included in the display unit, and reversely converting the communication information about the interface specifications for the CPU included in the display unit to the communication information about those for the computer. The interface converting means eliminates the need for replacement of the display unit or re-development of the CPU included in the display unit for the purpose of performing matching with the interface for the communications from the computer. When the removable interface specifications converting means is installed on the display unit, the position of its attachment is placed on the periphery or the like of a display screen of the display unit, whereby the operability of a user at the replacement can be improved. If the attached position of the interface specifications converting means is placed in the neighborhood of a power switch, for example, the facilitation of exchange for the user is improved as is the case with the turning on and off of the power. As an effect obtained by placing the attached position in the position around the display screen of the display unit, a similar effect can be obtained even in the case of the provision of the interface adapter used as interface means for allowing a converting means-free communication as well as in the case of the installation of the interface specifications converting means. Here, the communication employed in the present invention means that at least information such as a command can be bidirectionally transmitted and received between two apparatuses. Information including data information except for the command may be used as the above information.
While the function of performing mutual conversion between the above-described different interface specifications serves as one for the communications between the computer and the display unit, it is not limited to the communications between the computer and the display unit. Interface mutual conversion between commonly-used digital signal processing devices can be also carried out in the same manner by similar interface specifications converting means. Thus, the present invention provides a communication system which comprises interface specifications converting means for allowing mutual interface specification conversion for communications between digital signal processing devices different in interface specifications, a digital signal processing device provided with the interface specification converting means, a digital signal processing device having a portion to which the interface specification converting means is attached, and interface specifications converting means for performing mutual conversion between interface specifications for two digital signal processing devices and their communications.
The interface specifications converting means installed in the display unit is provided with a hub. A plurality of computers and a plurality of peripheral apparatuses are connectable to the hub. Here, the hub has a upstream port to which a computer is connected, and downstream ports to which peripheral apparatuses are connected, and freely performs mutual communications between the computer and the peripheral apparatuses through these ports. Owing to the connection of the computer and the peripheral apparatuses through the hub, one computer and a selected peripheral apparatus are communicable with each other. Even during its communication, the communication between the computer and another selected peripheral apparatus can be further carried out.
Further, the display unit according to the present invention is capable of having a memory area having stored therein an internal state of the display unit at its normal operation in addition to the conventional memory area for storing the information about the video signals and the video signal timing handleable by the display unit therein. Further, the display unit is able to have means for detecting the internal state of the display unit. Detailed operation information about the display unit can be obtained by a comparison between information about the internal state of the display unit at its normal condition, which is stored in the memory area, and the result of detection by the means for detecting the internal state of the present display unit.
Since the present invention is provided with the interface specifications converting means for converting the interface specifications of the computer connected for communication to the interface specifications handled or supported by the CPU included in the display unit, the present invention can cope even with a matrix type display unit as well as with a CRT (Cathode Ray Tube).
A display unit according to the present invention also comprises a video processing circuit to which video signals of R, G and B are inputted, a display device for performing a display based on the output of the video processing circuit, a drive circuit for driving the display device based on synchronizing signals inputted thereto together with the video signals, a CPU for controlling the video processing circuit and the drive circuit, and a hub unit for connecting peripheral apparatuses to an external computer. The display unit brings about another effect in that means for holing all or part of identification information transmitted to the hub unit is provided inside the display unit excluding the hub unit.
Further, a display unit according to the present invention for achieving the above objects comprises a video processing circuit to which video signals of R, G and B are inputted, a display device for performing a display based on the output of the video processing circuit, a drive circuit for driving the display device based on synchronizing signals inputted thereto together with the video signals, a CPU for controlling the video processing circuit and the drive circuit, and a hub unit for connecting peripheral apparatuses to an external computer. The display unit is characterized in that first recording means for holding all or part of identification information indicative principally of the display unit, which is transmitted to the hub unit is provided inside the display unit excluding the hub unit, and second recording means for holing all or part of identification information indicative principally of the hub unit is provided inside the hub unit.
Furthermore, means for holding all or some of the identification information transmitted to the hub unit may be provided inside the external computer.